The present invention relates to a method and an apparatus for diagnosing the mastitis based on visual light and/or near infrared spectra from urine, raw milk or mammary gland of cows.
The number of somatic cells in raw milk is an important factor for the mastitis diagnosis. Heretofore, a direct microscopy method, a CMT modified method, and a fluorometry have been used for measuring the number of the somatic cells.
At present, a fluorometrical type somatic cell counter (Fossomatic) is used to measure the number of the somatic cells in the raw milk. This apparatus can calculate and display the number of the somatic cells per 1 ml through mixing a buffer solution and a dying liquid (ethidium bromide solution) to the raw milk, fluorescently staining cell nuclei of the somatic cells, scatteredly applying the resulting mixture to a peripheral portion of a disc continuously rotated with use of a microsyringe, and automatically measuring the number of the somatic cells with the fluorescent microscope.
In Japan, it is prescribed that if the number of the somatic cells is 300,000 or more per 1 ml in the measurement of the raw milk with the fluorometrical type somatic cell counter (Fossomatic), the cow is judged to suffer the mastitis, and prohibited from being milked.
However, the conventional mastitis diagnosis method based on the measurement of the somatic cells with the fluorometrical type somatic cell counter has various problems to be solved, in that (1) the raw milk taken needs to be subjected to preliminary treatment with the addition of chemicals such as the buffer solution and the dying liquid; (2) the raw milk sample cannot be measured in a non-destructive manner (3) the raw material is likely to be influenced with another substance; (4) the prices of the chemicals are high, which is disadvantageous from the standpoint of the cost performance; and (5) skillful technical [method is required to handle the apparatus and the sample.
It is an object of the present invention to provide a measuring method and apparatus and a judgment method therefore, which perform the diagnosis of the mastitis at a high precision in a short time through the optical measurement of the visual light and/or near infrared spectra from urine, raw milk or a mammary gland of a cow.
The present invention relates to the method for diagnosing mastitis of cows, comprising the steps of irradiating visual light rays and/or near infrared rays in a wavelength range of 400 to 2500 nm into urine, raw milk or a mammary gland of a cow, detecting an intensity of transmitted light rays, reflected light rays or transmitted and reflected light rays from said urine, raw milk or mammary gland, effecting multivariate regression analysis, and diagnosing the presence of the mastitis of the cow. With respect to the visual light rays and/or the near infrared rays to be used for the detection, those in a wavelength judged effective for the diagnosis of the mastitis are selected.
According to the present invention, the absorbance, which varies depending upon the number of the somatic cells in urine, raw milk or mammary gland, can be determined by detecting the intensity of the transmitted light rays, reflected light rays or transmitted and reflected light rays from the urine, raw milk or mammary gland of the cow. Thus, the mastitis of the cow can be diagnosed by performing the multivariate regression analysis, and diagnosing the presence of the mastitis of the cow. Therefore, it is no need to effect the conventionally troublesome pretreatments, to use expensive chemicals, etc. and to skillfully handling samples. The intensity of the light rays, etc. reflected from the mammary gland means the intensity of the reflected light rays, etc. from the tissues of the living body including mammal cells. It is considered that mammary gland cells (including the raw milk) and the living tissues are milky and cuvette, respectively, in the mammary gland. As to the measurement of the transmitted light rays, for example, the incident light rays are applied to a one right side of the mammary gland through an optical fiber, and the transmitted light rays (on a side of the detector) are measured through another optical fiber applied to an another left side of the mammary gland, while the optical fiber is applied to a left side. The light rays in the near infrared range pass an even thick path in mammary gland depending upon the wavelength range.
The wavelength of the visual light rays and the near infrared rays to be used for the diagnosis of the mastitis in the present invention ranges from 400 nm to 2500 nm. If the visual light rays and the infrared rays in a range of 400 nm to 1100 nm are used, a silicon light detector is used. If the near infrared rays in the wavelength range of 700 nm to 2500 nm are used, a light detector of such as PbSe, InGaAs or GaAs is used.
Since the visual light rays and the near infrared ray in the range of 400 nm to 700 nm have noises it is preferable to use the near infrared rays in the range of 700 to 2500 nm among the above-mentioned wavelength range of the visual light rays and the near infrared rays. Further, since the raw milk contains various ingredients such as water, proteins, fat, carbohydrates, minerals, etc. and light rays are absorbed principally by water as the main ingredient at various wavelength regions, it may be feared that such will interrupt the measurement of the near infrared spectra. However, the water-related influence is smaller in the wavelength region of 700 to 2500 nm as compared with those in the other wavelength region. In the wavelength region of 1100 to 2500 nm, changes in the absorbance of the somatic cells in the urine, raw milk or mammary gland appear as first harmonic tone or combination tone of molecular vibrations. Therefore, the measurement is preferably made with the near infrared rays in the wavelength range of 1100 nm to 2500 nm, which enables measurement of the somatic cells in the urine, raw milk or mammary gland in a short time.
Moreover, since the intensity of the light absorption in the urine, raw milk or mammary gland is relatively small in the wavelength region of the infrared rays, the thickness of the sample can be ensured at a few or several mm in the measurement of the transmitted light rays or the transmitted and reflected light rays. Therefore, it is easy to handle and set a sample container.
The mastitis of the cows can be readily diagnosed at high precision through the optical measurement of the urine, raw milk or mammary gland and the data processing based on the multivariate regression. The method for the diagnosis of the cow mastitis, which uses the optical measurement values for the urine, raw milk or mammary gland and data processing based on the multivariate regression analysis, will be explained later.
The present invention is characterized in that the incident light rays, transmitted light rays, reflected light rays or transmitted and reflected light rays from the urine, raw milk or mammary gland in the optical measurement is scanned over the wavelengths by using a spectroscope, and the multivariate regression analysis is applied to the spectroscopic spectra obtained.
According to the present invention, since substantially continuous spectroscopy spectra having a high wavelength resolution can be obtained through scanning over the wavelengths with use of the spectroscope, such a large amount of data as required for the data analysis can be obtained. For example, if the scanning is effected in the wavelength region of 1100 to 2500 nm at a wavelength resolution of 2 nm, 701 data points can be taken in per one scanning, resulting in enhanced precision of the data analysis.
The present invention also relates to the apparatus for diagnosing mastitis of cows, comprising: (1) a near infrared ray generator for generating visual light rays and/or near infrared rays in a wavelength range of 400 nm to 2500 nm; (2) an optical system for introducing the visual light rays and/or near infrared rays into urine, raw milk or a mammary gland of a cow; (3) a detector for detecting an intensity of transmitted light rays, reflected light rays or transmitted and reflected light rays from said urine, raw milk or mammary gland; (4) and a data processor for receiving signals from said detector, and effecting multivariate regression analysis to diagnose the presence of the mastitis in cow.
The mastitis diagnosis apparatus according to the present invention preferably further comprises an optical fiber for leading visual light rays and/or near infrared rays from said urine, raw milk or a mammary gland of the cow to the light detector, so that the intensity of transmitted light rays, reflected light rays or transmitted and reflected light rays from said urine, raw milk or mammary gland is detected with said detector through the optical fiber.
The utilization of the optical fiber can provide a portable, compact mastitis diagnosis apparatus.
The cow mastitis-diagnosing apparatus preferably further comprises a feeder for introducing said raw milk into a raw milk sample container via an in-line or at line.
The provision of the feeder for introducing said raw milk into the sample container via an in-line or at line enables the continuous measurement of the visual light rays and/or near infrared rays with the lapse of time.
The cow mastitis-diagnosing apparatus further comprises a sample container for holding the raw milk, and a temperature controller for stabilizing the milk inside the sample container to a given temperature.
Stabilization of the temperature of the raw milk in the sample container can prevent variations in absorbance of the raw milk due to temperature, which can enhance the precision in the diagnosis of the mastitis. When the mammary gland is measured to diagnose the mastitis, the mammary gland is held with a milking machine, and the temperature is controlled in the same way as mentioned above, if necessary.